1. Field of the Invention
This invention relates to a mowing machine, which has a mowing blade unit and makes traveling with drive wheels driven by an engine.
2. Description of the Prior Art
A riding mowing machine manipulated by an operator seated on a traveling machine body is well known as a conventional mowing machine. This riding mowing machine involves a mowing machine having a vertically movable mowing unit below the traveling machine body and an engine in front or at the rear of the traveling machine body. The above mowing machine also has a transmission case close to the engine and applies drive force from the transmission case to drive front or rear wheels for allowing the traveling machine body to travel.
The above mowing machine further has a transmission mechanism between the mowing unit and the engine to transmit drive force from the engine to the mowing unit. The mowing unit is allowed to move upwards to bring the mowing unit to a stop for normal traveling requiring no mowing works. On the other hand, the mowing unit is allowed to move downwards for operative traveling requiring mowing works.
The above mowing machine performs the mowing works by allowing the traveling machine body to travel with the mowing unit driven after having allowed the mowing unit to move downwards.
On the other hand, for the purpose of avoiding a bad influence on stable traveling performance, the mowing machine permits no much vehicle height (the overall height), and hence, no quite large space below the traveling machine body. For that reason, when a four-wheel drive (4WD) mechanism is applied to a traveling drive system for improvement on traveling stability, for instance, it is difficult to place both a 4WD transmission system and a support mechanism of the mowing unit below the traveling machine body.
Accordingly, the placement of both the 4WD transmission system and the support mechanism of the mowing unit below the traveling machine body brings about such defects that a stroke of the mowing unit for upward or downward movement is made smaller and that a large space is not provided on the drive system side, resulting in a problem in an increase in restrictions on the specification of the mowing machine.
On the other hand, since the riding mowing machine normally uses pulleys and belts for the transmission mechanism of the mowing unit, the relative height of a pulley shaft on the input shaft side to a pulley shaft on the output shaft side and the vertical positions of both the pulley shafts vary with the upward or downward movement of the mowing unit, resulting in no smooth transmission of drive force in some cases.
It is a first object of the present invention to provide a four-wheel drive riding mowing machine having a mowing unit below a machine body such that the mowing machine has the overall height as much as traveling stability is maintained.
A second object of the present invention is to transmit drive force to the mowing unit smoothly when the mowing unit is allowed to move upwards or downwards.
The characteristics of the present invention for attaining the above objects are as follows.
Firstly, there is provided a mowing machine having a mowing unit below a traveling machine body, an engine in front or at the rear of the traveling machine body and a transmission case close to the engine. The mowing machine comprises a four-wheel drive mechanism for allowing driving front and rear wheels by transmitting drive force from the transmission case to rear and front axle cases, wherein a remote transmission part for transmitting the drive force to one axle case located more remote from the transmission case in the four-wheel drive mechanism is formed in an upwardly bent or curved shape, and a space for placement of the mowing unit is provided below the remote transmission part.
Secondly, the remote transmission part has a first transmission shaft connected to an output shaft for outputting the drive force from the transmission case to the more remote axle case, a second transmission shaft connected to an input shaft of the above axle case and a connection part for connecting the first and second transmission shafts together, and the first and second transmission shafts are connected together in the shape of an angle through the connection part.
Thirdly, the mowing unit is supported movably upwards or downwards.
Fourthly, an expansion shaft expansible in an axial core direction is provided in a transmission mechanism for supplying the drive force to the mowing unit.
Fifthly, the expansion shaft is composed of an externally cylindrical part and an inserted shaft inserted into the externally cylindrical part slidably in an axial core direction, while allowing transmission of the drive force of the externally cylindrical part in a rotary direction.
Sixthly, a gear case for allowing output of the drive force from the engine to the mowing unit is provided in the transmission mechanism, an output part of the gear case is one-sided leftwards or rightwards from the center of the traveling machine body, and an input end of the expansion shaft is connected to the output part.